Do not execute anything if a host is unreachable

If a host is unreachable, the default behaviour for
ansible is to ignore that and execute all the tasks
in the hosts that are reachable. This is unwanted
behaviour for B&R, as we need the whole controller
cluster to be healthy and reachable before we take
a backup from it. This patch introduces a mechanism
to abort execution if there is one or more
unreachable hosts.

Change-Id: I3820875e72a8d805d71c7981468398bbcec0bf04

tripleo_ansible/playbooks/cli-overcloud-backup-cron.yaml

@@ -13,6 +13,21 @@
 #   License for the specific language governing permissions and limitations
 #   under the License.
 
+- name: Do nothing if one of the hosts is unreachable
+  hosts: '{{ tripleo_controller_group_name }}'
+  become: true
+  vars_files:
+    ../roles/backup_and_restore/defaults/main.yml
+  tasks:
+    - name: Check ALL hosts are reacheable
+      fail:
+        msg: >
+          [REQUIRED] ALL hosts to be reachable, so flagging {{ inventory_hostname }} as failed,
+          because host {{ item }} has no facts, meaning it is UNREACHABLE.
+      when: "hostvars[item].ansible_facts|list|length == 0"
+      with_items: "{{ groups[tripleo_controller_group_name] }}"
+      run_once: true
+
 - name: TripleO Controller backup
   hosts: Undercloud
   become: true

tripleo_ansible/playbooks/cli-overcloud-backup.yaml

@@ -12,6 +12,22 @@
 #   WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #   License for the specific language governing permissions and limitations
 #   under the License.
+
+- name: Stop executing if one of the hosts is unreachable
+  hosts: '{{ tripleo_controller_group_name }}'
+  become: true
+  vars_files:
+    ../roles/backup_and_restore/defaults/main.yml
+  tasks:
+    - name: Check ALL hosts are reacheable
+      fail:
+        msg: >
+          [REQUIRED] ALL hosts to be reachable, so flagging {{ inventory_hostname }} as failed,
+          because host {{ item }} has no facts, meaning it is UNREACHABLE.
+      when: "hostvars[item].ansible_facts|list|length == 0"
+      with_items: "{{ groups[tripleo_controller_group_name] }}"
+      run_once: true
+
 - name: Backup ceph authentication
   hosts: ceph_mon
   become: true

tripleo_ansible/playbooks/prepare-overcloud-backup.yaml

@@ -13,6 +13,21 @@
 #   License for the specific language governing permissions and limitations
 #   under the License.
 
+- name: Stop executing if one of the hosts is unreachable
+  hosts: '{{ tripleo_controller_group_name }}'
+  become: true
+  vars_files:
+    ../roles/backup_and_restore/defaults/main.yml
+  tasks:
+    - name: Check ALL hosts are reacheable
+      fail:
+        msg: >
+          [REQUIRED] ALL hosts to be reachable, so flagging {{ inventory_hostname }} as failed,
+          because host {{ item }} has no facts, meaning it is UNREACHABLE.
+      when: "hostvars[item].ansible_facts|list|length == 0"
+      with_items: "{{ groups[tripleo_controller_group_name] }}"
+      run_once: true
+
 - name: TripleO Controller ReaR installation and configuration.
   hosts: '{{ tripleo_controller_group_name }}'
   remote_user: "{{ tripleo_target_user | default(lookup('env', 'USER')) }}"

tripleo_ansible/roles/backup_and_restore/tasks/main.yml

@@ -14,7 +14,6 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-
 # "backup_and_restore" will search for and load any operating system variable file
 
 # found within the "vars/" path. If no OS files are found the task will skip.